Some versions date the Francesinha to the 1960s. A returned emigrant from France and Belgium tried to adapt the croque-monsieur to Portuguese taste. It is said, other versions, that the Francesinha was invented in the 19th century. Is connotated with Oporto city, but, nowadays it can be sometimes found elsewhere in Portugal. A classic Francesinha meal would include the sandwich with famous sauce and chips, complemented with a beer.
The people from Porto refers that the restaurant with the best Francesinha in town is depending the quality of sauce and the quality of the meats.